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ExtJS实战(3)-spring

2010-12-02 22:10 176 查看
上一篇文章我们看到了hibernate的作用,但是我们并没有贴出具体的数据访问层的代码,这是因为我们既然要使用这么多框架,当然就希望它们能够“黏合”的很好,譬如,我们不想使用代码处理事务,也就是说想使用声明式事务。这当然就是Spring大显身手的地方了。我们来看一看数据访问层的代码,还是面向接口编程:

1.下面是一个接口,它告诉外界可以做哪些事情,譬如按条件分页查询房屋信息,增加,修改,删除房屋信息,得到符合条件的房屋总数等!

package org.leno.houseHire.dao;

import java.util.List;

import org.leno.houseHire.action.Condition;

import org.leno.houseHire.dao.House;

public interface IHouseDAO {

public List<House> findAllHouse(Condition cond,final int start ,final int limit);

public House findById(int id);

public void addHouse(House house);

public void editHouse(House house);

public int delHouse(List<String> ids);

public long getTotalNums(Condition cond);

public List<Area> getAllAreas();

public List<Street> getAllStreets(int aid);

public String getAreaNameById(int id);

public String getStreetNameById(int id);

public User getUserById(int id);

public Street getStreetById(int id);

}

2.下面是一个利用Hibernate访问数据库的DAO实现,我们看到,它还继承了HibernateDaoSupport这个类,这是Spring对Hibernate提供的一个帮助支持类,它不仅封装了Hiberntate的实现,还对Hibernate操作涉及的事务进行统一管理。

package org.leno.houseHire.dao;

import java.sql.SQLException;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import org.hibernate.Criteria;

import org.hibernate.HibernateException;

import org.hibernate.Query;

import org.hibernate.Session;

import org.hibernate.criterion.Order;

import org.hibernate.criterion.Projections;

import org.hibernate.criterion.Restrictions;

import org.leno.houseHire.action.Condition;

import org.leno.houseHire.dao.House;

import org.springframework.orm.hibernate3.HibernateCallback;

import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

public class HouseDAOImpl extends HibernateDaoSupport implements IHouseDAO {

public void addHouse(House house) {

getHibernateTemplate().save(house);

}

public void editHouse(House house) {

getHibernateTemplate().update(house);

}

@SuppressWarnings("unchecked")

public List<House> findAllHouse(Condition cond, final int start,

final int limit) {

final String title = cond.getTitle();

final int room = cond.getRoom();

final int ting = cond.getTing();

final int areaId = cond.getAreaId();

final int streetId = cond.getStreetId();

final double priceStart = cond.getPriceStart();

final double priceEnd = cond.getPriceEnd();

final String booktime = cond.getBooktime();

final String sort = cond.getSortCond();

// 更通用可以换成DetachedCriteria

return (List<House>) getHibernateTemplate().execute(

new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

Criteria cr = session.createCriteria(House.class)

.setFirstResult(start).setMaxResults(limit);

if (title != null && !title.trim().equals("")) {

cr.add(Restrictions

.like("title", "%" + title + "%"));

}

if (room != 0) {

cr.add(Restrictions.eq("room", room));

}

if (ting != 0) {

cr.add(Restrictions.eq("ting", ting));

}

if (streetId == 0) {

if (areaId != 0) {

cr.createCriteria("street").createCriteria(

"area").add(

Restrictions.eq("aid", areaId));

}

}

if (streetId != 0) {

cr.createCriteria("street").add(

Restrictions.eq("sid", streetId));

}

if (priceEnd > 0) {

cr.add(Restrictions.between("hireprice",

priceStart, priceEnd));

}

if (booktime != null && !booktime.trim().equals("")) {

String sda = booktime + " " + "00:00:00";

String eda = booktime + " " + "23:59:59";

SimpleDateFormat sdf = new SimpleDateFormat(

"yyyy-MM-dd HH:mm:ss");

try {

Date start_date = sdf.parse(sda);

Date end_date = sdf.parse(eda);

cr.add(Restrictions.between("booktime",

start_date, end_date));

} catch (ParseException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if (sort != null && sort.equals("desc")) {

cr.addOrder(Order.desc("booktime"));

}

List<House> list = cr.list();

return list;

}

});

}

/**

* 在Hibernate3中,对Criteria又增添了新功能,可以支持分组与统计功能,在Hibernate3中增加了Projections以及ProjectionList类,这两个类对分组与统计功能进行了封装

*/

public long getTotalNums(Condition cond) {

final String title = cond.getTitle();

final int room = cond.getRoom();

final int ting = cond.getTing();

final int areaId = cond.getAreaId();

final int streetId = cond.getStreetId();

final double priceStart = cond.getPriceStart();

final double priceEnd = cond.getPriceEnd();

final String booktime = cond.getBooktime();

return (Integer) getHibernateTemplate().execute(

new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

Criteria cr = session.createCriteria(House.class);

if (title != null && !title.trim().equals("")) {

cr.add(Restrictions

.like("title", "%" + title + "%"));

}

if (room != 0) {

cr.add(Restrictions.eq("room", room));

}

if (ting != 0) {

cr.add(Restrictions.eq("ting", ting));

}

if (streetId == 0) {

if (areaId != 0) {

cr.createCriteria("street").createCriteria(

"area").add(

Restrictions.eq("aid", areaId));

}

}

if (streetId != 0) {

cr.createCriteria("street").add(

Restrictions.eq("sid", streetId));

}

if (priceEnd > 0) {

cr.add(Restrictions.between("hireprice",

priceStart, priceEnd));

}

if (booktime != null && !booktime.trim().equals("")) {

String sda = booktime + " " + "00:00:00";

String eda = booktime + " " + "23:59:59";

SimpleDateFormat sdf = new SimpleDateFormat(

"yyyy-MM-dd HH:mm:ss");

try {

Date start_date = sdf.parse(sda);

Date end_date = sdf.parse(eda);

cr.add(Restrictions.between("booktime",

start_date, end_date));

} catch (ParseException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

// return cr.list().size();

cr.setProjection(Projections.count("hid"));

return cr.uniqueResult();

}

});

}

@SuppressWarnings("unchecked")

public List<House> findAllHouse2(Condition cond, final int start,

final int limit) {

String hql = "select h from House h where 1=1";

String title = cond.getTitle();

int room = cond.getRoom();

int ting = cond.getTing();

int areaId = cond.getAreaId();

int streetId = cond.getStreetId();

double priceStart = cond.getPriceStart();

double priceEnd = cond.getPriceEnd();

String booktime = cond.getBooktime();

String sort = cond.getSortCond();

if (title != null && !title.trim().equals("")) {

hql = hql + " and h.title like '%" + title + "%'";

}

if (room != 0) {

hql = hql + " and h.room=" + room;

}

if (ting != 0) {

hql = hql + " and h.ting=" + ting;

}

if (areaId != 0) {

hql = hql + " and h.street.area.aid=" + areaId;

}

if (streetId != 0) {

hql = hql + " and h.street.sid=" + streetId;

}

if (priceEnd > 0) {

hql = hql + " and h.hireprice between " + priceStart + " and "

+ priceEnd;

}

if (booktime != null && !booktime.trim().equals("")) {

// 用到sqlserver日期转化成字符串的函数

hql = hql + " and convert(char,h.booktime,23)='" + booktime + "'";

}

if (sort != null && sort.equals("desc")) {

hql = hql + " order by h.booktime desc";

}

System.out.println(hql);

final String finalHql = hql;

// Spring的HibernateTemplate提供了Hibernate的完美封装,即通过匿名类实现回调,来保证Session的自动资源管理和事务的管理。

return (List<House>) getHibernateTemplate().execute(

new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

Query query = session.createQuery(finalHql)

.setFirstResult(start).setMaxResults(limit);

return query.list();

}

});

}

public long getTotalNums2(Condition cond) {

String hql = "select count(h) from House h where 1=1";

String title = cond.getTitle();

int room = cond.getRoom();

int ting = cond.getTing();

int areaId = cond.getAreaId();

int streetId = cond.getStreetId();

double priceStart = cond.getPriceStart();

double priceEnd = cond.getPriceEnd();

String booktime = cond.getBooktime();

if (title != null && !title.trim().equals("")) {

hql = hql + " and h.title like '%" + title + "%'";

}

if (room != 0) {

hql = hql + " and h.room=" + room;

}

if (ting != 0) {

hql = hql + " and h.ting=" + ting;

}

if (areaId != 0) {

hql = hql + " and h.street.area.aid=" + areaId;

}

if (areaId != 0) {

hql = hql + " and h.street.area.aid=" + areaId;

}

if (streetId != 0) {

hql = hql + " and h.street.sid=" + streetId;

}

if (priceEnd > 0) {

hql = hql + " and h.hireprice between " + priceStart + " and "

+ priceEnd;

}

if (booktime != null && !booktime.trim().equals("")) {

// 用到sqlserver日期转化成字符串的函数

hql = hql + " and convert(char,h.booktime,23)='" + booktime + "'";

}

System.out.println(hql);

final String finalHql = hql;

return (Long) getHibernateTemplate().execute(new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

return session.createQuery(finalHql).uniqueResult();

}

});

}

@SuppressWarnings("unchecked")

public List<Area> getAllAreas() {

return (List<Area>) getHibernateTemplate().execute(

new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

Query query = session.createQuery("from Area");

return query.list();

}

});

}

@SuppressWarnings("unchecked")

public List<Street> getAllStreets(final int aid) {

return (List<Street>) getHibernateTemplate().execute(

new HibernateCallback() {

public Object doInHibernate(Session session)

throws HibernateException, SQLException {

Query query = session.createQuery(

"from Street s where s.area.aid=?")

.setInteger(0, aid);

return query.list();

}

});

}

public int delHouse(List<String> ids) {

int len = 0;

if (ids == null || ids.size() == 0) {

return len;

}

len = ids.size();

System.out.println("del........" + len);

List<House> list = new ArrayList<House>();

for (int i = 0; i < len; i++) {

House house = findById(Integer.parseInt(ids.get(i)));

list.add(house);

}

getHibernateTemplate().deleteAll(list);

return len;

}

public House findById(int id) {

House house = (House) getHibernateTemplate().get(House.class, id);

return house;

}

public String getAreaNameById(int id) {

return ((Area) getHibernateTemplate().get(Area.class, id)).getAname();

}

public String getStreetNameById(int id) {

return getStreetById(id).getSname();

}

public Street getStreetById(int id) {

return (Street) getHibernateTemplate().get(Street.class, id);

}

public User getUserById(int id) {

return (User) getHibernateTemplate().get(User.class, id);

}

}

上面的DAO实现代码非常重要,因为数据库的操作就靠它了。对于复杂的表单查询,我这里使用了些技巧,大家可以借鉴。一个是将所有的查询条件封装成了一个Condition类,这样接口中复杂查询方法的设计就很简洁。再就是我提供了拼凑HQL和QBC两种查询的实现,大家可以对比一下,特别是对于日期字段,这两种方式是如何处理的,好好参考一下。每个框架基本上都有自己核心的基于XML格式的配置文件,我们来看看Spring的核心配置文件:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

<bean id="sessionFactory"

class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">

<property name="configLocation"

value="classpath:hibernate.cfg.xml">

</property>

</bean>

<!-- Hibernate 事务管理 -->

<bean id="transactionManager"

class="org.springframework.orm.hibernate3.HibernateTransactionManager">

<property name="sessionFactory" ref="sessionFactory" />

</bean>

<bean id="baseTransactionProxy"

class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"

abstract="true">

<property name="transactionManager" ref="transactionManager" />

<property name="transactionAttributes">

<props>

<prop key="persist*">

PROPAGATION_REQUIRED,-Exception

</prop>

<prop key="remove*">

PROPAGATION_REQUIRED,-Exception

</prop>

<prop key="insert*">PROPAGATION_REQUIRED</prop>

<prop key="save">PROPAGATION_REQUIRED</prop>

<prop key="update*">PROPAGATION_REQUIRED</prop>

<prop key="edit*">PROPAGATION_REQUIRED</prop>

<prop key="del*">PROPAGATION_REQUIRED</prop>

<prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>

<prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>

<prop key="query*">PROPAGATION_REQUIRED,readOnly</prop>

<prop key="disPlay*">PROPAGATION_REQUIRES_NEW</prop>

</props>

</property>

</bean>

<!-- login module -->

<bean name="/login" class="org.leno.houseHire.action.LoginAction">

<property name="loginService" ref="loginService"></property>

</bean>

<bean id="loginService"

class="org.leno.houseHire.service.LoginServiceImpl">

<property name="loginDAO" ref="loginDAO"></property>

</bean>

<bean id="loginDAO" class="org.leno.houseHire.dao.LoginDAOImpl">

<property name="sessionFactory" ref="sessionFactory"></property>

</bean>

<!-- hosue module -->

<bean name="/house" class="org.leno.houseHire.action.HouseSearchAction" lazy-init="true"

singleton="true">

<property name="houseService">

<ref bean="houseService"/>

</property>

</bean>

<bean name="/houseExport" class="org.leno.houseHire.action.HouseExportAction">

<property name="houseService">

<ref bean="houseService"/>

</property>

</bean>

<bean name="/houseHandler" class="org.leno.houseHire.action.HouseHandlerAction" lazy-init="true"

singleton="true">

<property name="houseService">

<ref bean="houseService"/>

</property>

</bean>

<bean id="houseServiceTarget" class="org.leno.houseHire.service.HouseServiceImpl" >

<property name="houseDAO">

<ref bean="houseDAO"/>

</property>

</bean>

<bean id="houseService" parent="baseTransactionProxy">

<property name="target">

<ref bean="houseServiceTarget"/>

</property>

</bean>

<bean id="houseDAO" class="org.leno.houseHire.dao.HouseDAOImpl" lazy-init="true"

singleton="true">

<property name="sessionFactory">

<ref bean="sessionFactory"/>

</property>

</bean>

</beans>

我们可以看到,在上面IOC和AOP的概念都得到了强有力的体现。怎么说呢?上面所有bean以及bean之间的依赖关系都是由Spring的IOC容器来管理的,譬如我们上面主要配置了四种bean:Action->Service->DAO->SessionFactory,后面的bean做前面bean的属性,也就是前面的bean依赖于后面的bean,而我们在代码中使用前面bean实例的时候,是不需要主动去寻找所依赖的后面bean的实例的,因为容器已经帮我们把依赖关系设置好了。这就是IOC(也叫DI,依赖注入),那么,AOP是怎么体现的呢?大家仔细分析上面的配置,我们发现Service除了有一个目标对象houseServiceTarget,还有一个代理对象houseService,而在Action里我们使用的是代理对象。咿,我们为什么要做这样一个代理对象呢?回想我们前面提到的事务管理,哦,明白了。Spring对Service层中的方法做了声明式事务管理。也就是说,当Service层调用DAO层对数据库进行操作时,根本不需要显式地写JAVA代码来开启或提交事务,而只需要利用Spring的配置文件就可以将Service层中的方法调用置身在事务管理中!嘿,这是一个非常强大的信号!有了AOP,意味这以后我们可以将一些系统级的服务,譬如日志处理,性能监控,安全管理,异常处理,事务管理等都单独地抽离处理,当业务模块需要这些服务的时候,我们要做的并不是修改代码,而是修改配置文件!这样,我们就可以做出更加松耦合的应用!
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